The effect of coupling on bubble fragmentation acoustics
Czerski, Helen and Deane, Grant B. (2011) The effect of coupling on bubble fragmentation acoustics. Journal of the Acoustical Society of America, 129, (1), 74-84. (doi:10.1121/1.3514416).
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Understanding the formation and evolution of bubble populations is important in a wide range of situations, including industrial processes, medical applications, and ocean science. Passive acoustical techniques can be used to track changes in the population, since each bubble formation or fragmentation event is likely to produce sound. This sound potentially contains a wealth of information about the fragmentation process and the products, but to fully exploit these data it is necessary to understand the physical processes that determine its characteristics. The focus of this paper is binary fragmentation, when turbulence causes one bubble to split into two. Specifically, the effect that bubble-bubble coupling has on the sound produced is examined. A numerical simulation of the acoustical excitation of fragmenting bubbles is used to generate model acoustic signals, which are compared with experimental data. A frequency range with a suppressed acoustic output which is observed in the experimental data can be explained when coupling is taken into account. In addition, although the driving mechanism of neck collapse is always consistent with the data for the larger bubble of the newly formed pair, a different mechanism must be driving the smaller bubble in some situations.
|Additional Information:||This paper describes the first study to examine acoustical coupling between two new bubbles generated by the fragmentation of a larger bubble. Detailed bubble size distributions are important for both oceanography and chemical engineering, and the sound emitted by fragmentation events provides data about the bubbles produced in complex turbulence environments. Inclusion of the research described here will improve the accuracy of that data. This paper combines experiment and theory to explain previously observed anomalies in bubble data, and the outcomes are currently being used in models of bubble formation underneath breaking waves in the ocean.|
|Keywords:||acoustic emission, acoustic signal processing, bubbles, numerical analysis, turbulence|
|Subjects:||Q Science > QC Physics
T Technology > TA Engineering (General). Civil engineering (General)
|Divisions:||University Structure - Pre August 2011 > Institute of Sound and Vibration Research > Fluid Dynamics and Acoustics
|Date Deposited:||28 Apr 2011 08:54|
|Last Modified:||27 Mar 2014 19:35|
|RDF:||RDF+N-Triples, RDF+N3, RDF+XML, Browse.|
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